JPH083280A - Resin composition - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin/phenolic resin composition for use in sealing which has satisfactory storage stability at ordinary temp. by using a salt of a specific curing accelerator with a specific organic compound which salt begins to react with a phenolic novolak hardener at 70 deg.C or higher. CONSTITUTION:1,8-Diazabicyclo[5,4,0]-7-undecene (DBU) is reacted with an organic compound (A) forming an ion pair together with DBU to obtain a salt (B) which satisfies the following. When 70 pts.wt. phenolic novolak having a number-average mol.wt. of 500, a softening point of 95 deg.C, and a hydroxyl equivalent of 104 is mixed with the salt (B) in an amount of 30 pts.wt. in terms of DBU amount and this mixture is analyzed by differential scanning calorimetry at a heating rate of 10 deg.C/min, an exothermic reaction begins at 70 deg.C or higher. Preferred examples of the compound (A) include terephthalic acid, which heightens the temperature at which the reaction initiates. A blend of an epoxy resin with a phenolic resin in such a proportion as to result in an equivalent ratio of the epoxy groups to the phenolic hydroxyl groups of 0.5-2 is melt- kneaded together with 0.5-20 pts.wt. the salt (B) as a curing accelerator and 40-2,400 pts.wt. inorganic filler per 100 pts.wt. the blend to produce a resin composition for an electronic part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for electronic and electric parts which is excellent in curability and has good storage stability at room temperature.

[0002]

2. Description of the Related Art In recent years, epoxy resin compositions have been generally used as a sealing material for semiconductor elements such as ICs and LSIs and electric parts, from the viewpoint of characteristics and cost balance.

In such an epoxy resin sealing material,
Conventionally used curing accelerators include 2-methylimidazole, DBU, triphenylphosphine, and the like, but epoxy resin encapsulants using these curing accelerators have poor storage stability at room temperature, and therefore, room temperature. When stored at 1, there was a problem that unfilled defects occurred during molding due to deterioration of flowability, and gold wires of IC chips were broken, leading to defective conduction. For this reason, at present, it is necessary to store the epoxy resin encapsulating material in a refrigerating state, and it is the current situation that a great deal of cost is required for refrigerating storing and refrigerating transportation.

Further, Japanese Patent Publication No. 62-1612 describes that the use of a reaction product of DBU and an aromatic trivalent carboxylic acid as a curing accelerator improves the preservability of the encapsulant. The reaction product is described only as a solid reaction product at room temperature, and there is no mention of how the curing accelerator behaves in the resin to improve the storage stability of the resin composition. Furthermore, as a result of examination on a reaction product of DBU and an aromatic trivalent carboxylic acid (hereinafter, abbreviated as "reaction product") disclosed in Japanese Patent Publication No. 62-1612, a phenol, which is a curing agent which will be described in detail later, is obtained. In differential scanning calorimetry of the mixture of novolac and "reactant", the phenomenon of exotherm starting at low temperatures below 70 ° C was captured. We have found that there is a close relationship between this exothermic onset temperature and the storability of the resin composition, and have established a technique capable of providing a resin composition having extremely good storability. The details of the contents are described below.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a resin composition for electronic and electric parts, which has excellent curability and storage stability at room temperature.

[0006]

The present invention provides an epoxy resin (A) having two or more epoxy groups in one molecule and a phenol resin (B) having two or more phenolic hydroxyl groups in one molecule. The equivalent ratio of the group to the phenolic hydroxyl group is 0.5 or more and 2 or less, and further, as a curing accelerator, 1,8-diazabicyclo [5,4,0] -7-
A salt (D) comprising undecene (hereinafter abbreviated as DBU) and an organic compound (C) that forms an ion pair with DBU by giving at least one proton to this DBU, and this salt (D) is a number average This phenol novolac and salt (D) were mixed so that the ratio of DBU was 30 parts by weight with respect to 70 parts by weight of phenol novolac having a molecular weight of 500, a softening point of 95 ° C. and a hydroxyl group equivalent of 104, and the temperature was raised at 10 ° C./min. It is defined as a salt having an exothermic start temperature of 70 ° C. or higher when performing differential scanning calorimetry at a temperature rate,
This salt (D) was added to 100 parts by weight of (A) + (B).
A resin composition containing 0.5 parts by weight or more and 20 parts by weight or less and further containing 40 parts by weight or more and 2400 parts by weight or less of inorganic filler (E) with respect to 100 parts by weight of (A) + (B). is there.

Specific examples of the epoxy resin (A) include orthocresol novolac epoxy, phenol novolac epoxy, bisphenol A type epoxy,
Examples thereof include biphenyl type epoxy, but are not limited thereto. Further phenol resin (B)
Examples thereof include phenol novolac and cresol novolac. In these (A) and (B), the equivalent ratio of the epoxy group to the phenolic hydroxyl group is 0.5.
It is preferably 2 or more, and outside this range, problems such as lower glass transition temperature and lower curability occur.

In the salt (D) of DBU which is a curing accelerator and the organic compound (C), the organic compound (C) which donates a proton to DBU forms at least one proton to form an ion pair. This is a DBU
The salt (D) of the compound and the organic compound (C) will be described in detail.

Generally, an epoxy resin molding material using a phenol resin as a curing agent, especially an epoxy resin encapsulating material, undergoes a kneading process while heating and melting using a hot roll or an extruder in a trial production process of the material ( This is also described in the example in Japanese Patent Publication No. 62-1612), and the temperature of the material during the heating and kneading is 6
It is said that the temperature of 0 ° C. or higher, preferably 70 ° C. or higher is necessary for uniformly mixing and kneading the components in the material. In such a process, we have found that the curing accelerator in the material is sufficiently activated (this activation is commonly referred to as anion polymerization catalyst, for example, DBU is added to the acidic hydroxyl group of phenol novolac as the curing agent). If it means that an active species that contributes to the curing reaction is generated), the preservability of the material (resin composition in this specification) at a so-called normal temperature of about 25 to 40 ° C. is deteriorated. Therefore, the reaction start temperature between the salt (D) of DBU and the organic compound (C) and the curing agent phenol novolac (the reaction start temperature here means that the salt (D) is dissociated by heat and liberated DBU). Means substantially the temperature at which the addition of phenol to the hydroxyl group of phenol novolac begins, as described above. Normally, the reaction of adding DBU to the phenolic hydroxyl group is an exothermic reaction. Scanning calorimeter (hereinafter abbreviated as DSC) in those that can be detected sufficiently monitor) and a result of examining the storage stability of the relationship of the resin composition, the reaction starting temperature (exothermic onset temperature in DSC measurement to be described later) is 7
It was found that the storage stability at room temperature was remarkably improved at 0 ° C or higher. That is, this is a fact that suggests that if the production of active species is suppressed in the above-mentioned heat-kneading step, the room temperature preservability is improved.

Therefore, a specific method for detecting the reaction start temperature will be described in detail. The phenol novolac used has a number average molecular weight of 500, a softening point of 95 ° C. (softening point according to the ball ring method) and a hydroxyl equivalent of 104, and the ratio of DBU is 30 parts by weight with respect to 70 parts by weight of this phenol novolac. The amount of salt (D) is set to 1, and a mixture of phenol novolac and salt (D) is prepared. This mixture is measured by DSC in a nitrogen atmosphere at a temperature rising rate of 10 ° C./min to detect the heat generation start temperature. The organic compound (C) is not particularly limited as long as it satisfies the condition that the heat generation starting temperature is 70 ° C. or higher, but terephthalic acid, pyromellitic acid, 2,
6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, polyacrylic acid and the like have a high exothermic onset temperature and bring particularly preferable results in terms of storage stability and curability of the resin composition.

Further, the amount of the curing accelerator (D) added is 1 total weight of the epoxy resin (A) and the phenol resin (B).
It is preferably 0.5 parts by weight or more and 20 parts by weight or less with respect to 00 parts by weight. If the amount is less than 0.5 parts by weight, the curability will be deteriorated, and if the amount is more than 20 parts by weight, the curing will be too fast and problems such as unfilling failure will occur during molding.

Examples of the inorganic filler used in the present invention include alumina, fused silica, crystalline silica, clay and talc, but the inorganic filler is not particularly limited thereto. The amount of the inorganic filler (E) added is the resin component (A),
40 parts by weight or more based on 100 parts by weight of (B) 2
It is preferably 400 parts by weight or less, and when it is less than 40 parts by weight, it causes a problem such as a decrease in strength when it is used as a molding material, and when it is more than 2400 parts by weight, fluidity deteriorates and a problem such as unfilling failure during molding occurs Occurs. In addition, there is no problem to add a conventionally known additive to the resin composition of the present invention as needed. Specific examples include a release agent, a flame retardant such as antimony oxide and a halide, a pigment such as carbon black, and a surface treatment agent for an inorganic filler such as a silane coupling agent.

[0013]

[Function] DBU and organic compound (C) used in the present invention
The salt (D) is a compound in which the organic compound (C) donates at least one proton to DBU to form an ion pair, and the curing accelerator (D) has a temperature of room temperature to a kneading temperature. In the region, the ion pair (salt) of DBU and the organic compound (C) is stably present, which suppresses the catalytic action of DBU and dissociates quickly during molding when exposed to high temperature, and DBU becomes active. And has the effect of promoting curing. The curing accelerator (D) is preferably 0.5 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the total weight of the epoxy resin (A) and the phenol resin (B),
If the amount is less than 0.5 parts by weight, the curability is lowered, and if the amount is more than 20 parts by weight, the curing is too fast and the fluidity is lowered at the time of molding, which causes problems such as unfilling failure.

[0014]

EXAMPLES The present invention will be described in more detail below with reference to examples.

(Synthesis Example 1) N, N-dimethylformamide (DMF) 6 was added to a 200 ml round bottom flask equipped with a cooling tube.
0 g and 3.27 g of terephthalic acid were added, and when completely dissolved, 3.0 g of DBU was slowly added dropwise. White crystals started to form during the dropping. After the addition of DBU was completed, the reaction was allowed to proceed for 1 hour.
Vacuum dried in DBU and terephthalic acid salt (hereinafter DB
U-TPA) was obtained.

(Synthesis example 2) 150 g of tetrahydrofuran in a 300 ml three-neck separable flask equipped with a cooling tube,
20.0 g of p-nitrobenzoic acid was added, and when it was completely dissolved, 18.2 g of DBU was slowly added dropwise. The precipitated salt was filtered, dried in vacuum at 80 ° C., and then DBU and p-
A salt of nitrobenzoic acid (hereinafter abbreviated as DBU-NBA) was obtained.

(Synthesis Example 3) 300 g of acetone and 30.0 g of pyromellitic acid were placed in a 500 ml three-neck separable flask equipped with a cooling tube, and when completely dissolved, DBU was added.
18.0 g was slowly added dropwise. The deposited salt was filtered and vacuum dried at 80 ° C. to obtain a salt of DBU and pyromellitic acid (hereinafter abbreviated as DBU-PMA).

(Synthesis Example 4) N-methylpyrrolidone (NM) was placed in a 300 ml three-neck separable flask equipped with a cooling tube.
P) 150 g, 2,6-naphthalenedicarboxylic acid 10.0
g was added and heated to 100 ° C. to completely dissolve 2,6-naphthalenedicarboxylic acid. After that, 7.0 g of DBU was slowly added dropwise, and after the completion of the addition, the mixture was stirred for 1 hour and then gradually cooled to room temperature while continuing the stirring, and the precipitated salt was filtered, washed with toluene, and dried in vacuum at 80 ° C. to obtain DBU. Salt of 2,6-naphthalenedicarboxylic acid (hereinafter DBU-2,6
-Abbreviated as NDC).

(Synthesis example 5) 300 g of tetrahydrofuran in a 500 ml three-neck separable flask equipped with a cooling tube,
Add 20.0 g of 1,4-naphthalenedicarboxylic acid, and add 60
The mixture was heated to 0 ° C. to completely dissolve 1,4-naphthalenedicarboxylic acid. After that, 14.1 g of DBU was slowly added dropwise, and after the addition was completed, the precipitated salt was filtered and dried under vacuum at 80 ° C. to obtain DBU and a salt of 1,4-naphthalenedicarboxylic acid (hereinafter referred to as DBU-1,4-NDC For short).

(Synthesis Example 6) In a 300 ml three-neck separable flask equipped with a cooling tube, 80 g of methanol and 15.0 g of polyacrylic acid AC-10P manufactured by Toagosei Chemical Industry Co., Ltd.
Then, when dissolved, 31.7 g of DBU was slowly added dropwise. After reacting for 1 hour after completion of dropping, 10
After heating to 0 ° C. and distilling off 45 g of methanol to concentrate the reaction product, it was transferred to a vat and dried under vacuum at 100 ° C. to obtain DB.
A salt of U and polyacrylic acid (hereinafter abbreviated as DBU-PA) was obtained.

(Synthesis Example 7) 55 g of trimellitic acid and DBU were placed in a 300 ml three-neck separable flask equipped with a cooling tube.
39.8g was added and the temperature was raised to 160 ° C over 3 hours and then reacted for 30 minutes, the contents were transferred to a vat, allowed to cool in a desiccator, and brown resinous DBU and trimellitic acid salt (hereinafter abbreviated as DBU-TMA) ) Got.

Example 1 (1) Phenol novolac having a number average molecular weight of 500, a softening point of 95 ° C. and a hydroxyl equivalent of 104 (manufactured by Sumitomo Durez Co., Ltd.)
PR-51714) 3.5 g, DBU-obtained in Synthesis Example 1
3.15 g of TPA (1.5 g of DBU is contained in this) was mixed in a mortar, and DSC measurement was performed at a temperature rising rate of 10 ° C./min in a nitrogen atmosphere. As a result, the heat generation starting temperature was 80.3 ° C.

(2) Epoxy equivalent 21 at a softening point of 65 ° C.
Orthocresol novolak epoxy (EOCN-1025-65 manufactured by Nippon Kayaku Co., Ltd.) of 0 (67 parts (all parts by weight are hereinafter abbreviated)), phenol novolak having a softening point of 105 ° C. and a hydroxyl equivalent of 104 (Sumitomo Dures Co., Ltd. ) PR-51470) 33 parts, Synthetic Example 1 as a curing accelerator
DBU-TPA (1.7 parts), fused silica (300 parts),
2 parts of carnauba wax was blended and kneaded with a hot roll at 85 ° C. for 5 minutes. The actually measured temperature of the material at this time was 71 ° C. 17 by transfer molding of the obtained molding material
The spiral flow at 5 ° C. was 75 cm, and the Barcol hardness in molding at 175 ° C. for 60 seconds was 82. The spiral flow is a fluidity parameter, and the larger the value, the better the fluidity. The Barcol hardness is a curability parameter, and the larger the value, the better the curability.

Next, the spiral flow of this material after storage at 25 ° C. for 6 months was measured. As a result, the spiral flow was 71 cm, and the flow residual rate (flow after storage for 6 months at 25 ° C./initial flow × 100 (%)) was 95%.

(Example 2) (1) 3.15 g of DBU-TPA of (1) of Example 1
When DSC measurement was carried out in the same manner as in (1) of Example 1 except that 3.1 g of DBU-NBA obtained in Synthesis Example 2 was used, the exothermic onset temperature was 72.3 ° C. (2) The same procedure as in (2) of Example 1 was carried out except that 2.2 parts of DBU-NBA was used instead of 1.7 parts of DBU-TPA in (2) of Example 1. This material had a spiral flow of 85 cm and a Barcol hardness of 74. The spiral flow after storage at 25 ° C for 6 months was 77 cm, and the residual flow rate was 91%.

(Example 3) (1) 3.15 g of DBU-TPA of (1) of Example 1
When DSC measurement was carried out in the same manner as in (1) of Example 1 except that 4.0 g of DBU-PMA obtained in Synthesis Example 3 was replaced by DSC, the exothermic onset temperature was 80.3 ° C. (2) A material was prepared in the same manner as in (2) of Example 1 except that 4.0 parts of DBU-PMA was used instead of 1.7 parts of DBU-TPA in (2) of Example 1. This material had a spiral flow of 78 cm and a Barcol hardness of 85. The spiral flow after storage at 25 ° C for 6 months was 75 cm, and the residual flow rate was 96%.

(Example 4) (1) 3.15 g of DBU-TPA of (1) of Example 1
Was operated in the same manner as in (1) of Example 1 except that 3.6 g of DBU-2,6-NDC obtained in Synthesis Example 4 was replaced with DSC.
Upon measurement, the exothermic onset temperature was 92.4 ° C. (2) The same operation as in (2) of Example 1 was performed except that 1.9 g of DBU-2,6-NDC was used instead of 1.7 parts of DBU-TPA in (2) of Example 1. Made into a material.
This material had a spiral flow of 82 cm and a Barcol hardness of 86. The spiral flow after storage at 25 ° C for 6 months was 81 cm, and the residual flow rate was 99%.

Example 5 (1) 3.15 g of DBU-TPA of (1) of Example 1
Was replaced by the same procedure as in (1) of Example 1 except that 3.6 g of DBU-1,4-NDC obtained in Synthesis Example 5 was used.
Upon measurement, the exothermic onset temperature was 78.0 ° C. (2) The same operation as in (2) of Example 1 was performed except that 1.9 g of DBU-1,4-NDC was used instead of 1.7 parts of DBU-TPA in (2) of Example 1. Made into a material.
This material had a spiral flow of 77 cm and a Barcol hardness of 81. The spiral flow after storage at 25 ° C for 6 months was 72 cm, and the residual flow rate was 94%.

Example 6 (1) 3.15 g of DBU-TPA of (1) of Example 1
When DSC measurement was carried out in the same manner as in (1) of Example 1 except that 2.2 g of DBU-PA obtained in Synthesis Example 6 was used, the exothermic onset temperature was 81.0 ° C. (2) The same procedure as in (2) of Example 1 was carried out except that 2.4 parts of DBU-PA was used instead of 1.7 parts of DBU-TPA in (2) of Example 1. This material had a spiral flow of 73 cm and a Barcol hardness of 84. The spiral flow after storage at 25 ° C for 6 months was 71 cm, and the residual flow rate was 97%.

Example 7 67 parts of biphenyl type epoxy (YX-4000H manufactured by Yuka Shell Epoxy Co., Ltd.), a phenol novolak having a softening point of 95 ° C. and a hydroxyl equivalent of 103 (PR-51714 manufactured by Sumitomo Durez Co., Ltd.) 33 parts, 3.4 parts of DBU-TPA obtained in Synthesis Example 1 as a curing accelerator,
A material was prepared in the same manner as in (2) of Example 1 except that 2300 parts of fused silica was used. This material had a spiral flow of 52 cm and a Barcol hardness of 63 at 60 seconds. The spiral flow after storage at 25 ° C for 6 months was 49 cm, and the residual flow rate was 94%.

Comparative Example 1 (1) 3.15 g of DBU-TPA of (1) of Example 1
When the DSC measurement was carried out in the same manner as in (1) of Example 1 except that DBU was changed to 1.5 g, the exothermic onset temperature was 63.1 ° C. (2) A material was prepared in the same manner as in (2) of Example 1 except that 0.8 part of DBU-TPA was used instead of 1.7 parts of DBU-TPA in (2) of Example 1. This material had a spiral flow of 76 cm and a Barcol hardness of 71. The spiral flow after storage at 25 ° C for 6 months was 53 cm, and the residual flow rate was 70%.

(Comparative Example 2) All of Example 1 except that 30 parts of orthocresol novolac epoxy and 70 parts of phenol novolac were used in place of 67 parts of orthocresol novolac epoxy and 33 parts of phenol novolac of (2) of Example 1 It was made into a material by the same operation as. An attempt was made to measure the spiral flow of this material, but it could not be measured due to poor curing.

(Comparative Example 3) The curing accelerator DBU-TPA in Example 2 (2) was replaced with 1.7 parts of the curing accelerator DB.
All were made into a material by the same operation as in Example 1 except that 30 parts of U-TPA was used, but the curing was too fast and molding was impossible.

(Comparative Example 4) A material was prepared in the same manner as in (2) of Example 1 except that 3000 parts of fused silica was used instead of 300 parts of fused silica in (2) of Example 1. However, it had almost no fluidity and could not be molded.

Comparative Example 5 (1) 3.15 g of DBU-TPA of (1) of Example 1
When DSC measurement was carried out in the same manner as in (1) of Example 1 except that 3.6 g of DBU-TMA obtained in Synthesis Example 7 was used, the exothermic onset temperature was 64.2 ° C. (2) A material was prepared in the same manner as in (2) of Example 1 except that 3.3 parts of DBU-TMA was used instead of 1.7 parts of DBU-TPA in (2) of Example 1. This material has a spiral flow of 83 cm and a Barcol hardness of 8
It was 0. The spiral flow after storage at 25 ° C for 6 months was 62 cm, and the residual flow rate was 75%.

The results of Examples 1 to 7 and Comparative Examples 1 to 5 are summarized in Table 1.

[0037]

[Table 1]

[0038]

The resin composition according to the present invention has excellent curability and very good storage stability at room temperature. When the resin composition according to the present invention is used as a material for electronic and electric parts,
There are great advantages for the industry, such as refrigeration storage and refrigeration transportation are unnecessary.

Claims (6)

[Claims] 1. In an epoxy resin (A) having two or more epoxy groups in one molecule and a phenol resin (B) having two or more phenolic hydroxyl groups in one molecule, the equivalent ratio of epoxy groups to phenolic hydroxyl groups. Is 0.5 or more and 2 or less, and further 1,8-diazabicyclo [5,4,0] -7-undecene (hereinafter abbreviated as DBU) as a curing accelerator and at least one proton is given to this DBU. And a salt (D) consisting of an organic compound (C) forming an ion pair, and this salt (D) is used for 70 parts by weight of phenol novolac having a number average molecular weight of 500, a softening point of 95 ° C. and a hydroxyl equivalent of 104. , DBU in an amount of 30 parts by weight, the phenol novolac and the salt (D) were mixed, and the differential scanning calorimetry was carried out at a heating rate of 10 ° C./min. Are those starting temperature is defined as a salt which is a 70 ° C. or higher, the salt (D),
0.5 to 20 parts by weight per 100 parts by weight of (A) + (B), and the inorganic filler (E) is (A)
+ (B) 100 parts by weight, 40 parts by weight or more 2400
A resin composition containing less than or equal to parts by weight. 2. The resin composition according to claim 1, wherein the organic compound (C) according to claim 1 is terephthalic acid. 3. The resin composition according to claim 1, wherein the organic compound (C) according to claim 1 is pyromellitic acid. 4. The resin composition according to claim 1, wherein the organic compound (C) according to claim 1 is 2,6-naphthalenedicarboxylic acid. 5. The resin composition according to claim 1, wherein the organic compound (C) according to claim 1 is 1,4-naphthalenedicarboxylic acid. 6. The resin composition according to claim 1, wherein the organic compound (C) according to claim 1 is polyacrylic acid.